How to Replace the Engine Oil Cooler Line in a 91 Chevy 5.7L

The 1991 Chevy 5.7L transmission is used in the 350 truck produced by the General Motors corporation. This transmission assembly has two engine oil cooler lines that connect the radiator and the transmission. Oil runs through one of the lines into the radiator to reduce the temperature and then it runs back through the other line into the transmission to cycle through again. Replacing the lines when there is a leak is required to maintain the correct fluid levels in the engine.

Instructions

1

Slide beneath the truck's engine to locate the transmission and the radiator. The ports for the oil cooler lines are in the passenger's side of the transmission and the bottom of the radiator. Find the transmission by looking in the center, just off the driver's side for a black tank surrounded by eight bolts. Look for the radiator in the center of the engine: this is a large block that takes up the majority of the engine.

2

Shine a flashlight onto both the transmission and radiator to find the oil cooler line ports. These ports are circular and 3/8 inch thick with a connection for a nut extending outward.

3

Connect a 3/8 inch nut to both ends of each oil cooler line hose. Run one line from the transmission to the radiator.

4

Place the end of the hose in the port and then twist the nut with the flare nut wrench to tighten it onto the radiator and transmission. Repeat with the other length of hose.